Dynamical Nonlinear Inversion of the Surface Photovoltage at Si(100)

Friedrich Roth, Johannes Mahl, Mario Borgwardt, Lukas Wenthaus, Felix Brausse, Valentin Garbe, Oliver Gessner, and Wolfgang Eberhardt

Phys. Rev. Lett. 132, 146201 – Published 3 April 2024

Abstract

A surface photovoltage (SPV) is observed whenever a doped semiconductor with non-negligible band bending is illuminated by light and charge carriers are excited across the band gap. The sign of the SPV depends on the nature of the doping, the amplitude of the SPV increases with the fluence of the light illumination up to a saturation value, which is determined by the doping concentration. We have investigated Si(100) samples with well-characterized doping levels over a wide range of illumination fluences. Surprisingly, the sign of the SPV upon illumination with 532 nm photons reverses for some $p$ -doping concentrations at high fluences. This is a new effect associated with a crossover between electronic excitations in the bulk and at the surface of the semiconductor.

Received 15 September 2022
Revised 2 January 2024
Accepted 14 February 2024

DOI:https://doi.org/10.1103/PhysRevLett.132.146201

Physics Subject Headings (PhySH)

Photoinduced effect Surface states

Synchrotron radiation facilities

Ultrafast pump-probe spectroscopy X-ray photoelectron spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Friedrich Roth ^1,2,*, Johannes Mahl ³, Mario Borgwardt ³, Lukas Wenthaus ⁴, Felix Brausse^3,‡, Valentin Garbe ⁵, Oliver Gessner ³, and Wolfgang Eberhardt ^4,†

¹Institute of Experimental Physics, TU Bergakademie Freiberg, 09599 Freiberg, Germany
²Center for Efficient High Temperature Processes and Materials Conversion (ZeHS), TU Bergakademie Freiberg, 09599 Freiberg, Germany
³Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
⁴Center Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
⁵Institute of Applied Physics, TU Bergakademie Freiberg, 09599 Freiberg, Germany

^*Corresponding author: friedrich.roth@physik.tu-freiberg.de
^†Corresponding author: wolfgang.eberhardt@cfel.de
^‡Present address: European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany.